In the type of solutions presented above it is usual to arrange the scraper bars in a way, that they are being transfered by means of chains placed at the edges of the reservoir in a way, that they scrape in connection with the bottom material existing therewith to a sludge pocket and that they lead material correspondingly on the surface to a collecting chute, that goes cross the reservoir. In this connection, the scraper bars have been carried out by profiles, that are often made of, for example, fiberglass, and that are attached to the chains traditionally by a screw joint. A disadvantage of totally uniform scraper bars is particularly the troublesome installation of the same, whereby very accurate and careful installation measures are required, so that the holes to be made in the scraper bars are just in the right positions. This causes often several problems in practice, for example because of unevenness of the bottom of the clarification basin and because of other reasons as well. That is why the holes must often be left to be done on-site during installation. One disadvantage of the type of scraper bars described above is furthermore that, that they are placed always without exception totally one-sided in respect to the chains. That is why attachment of the same causes always resonance during use of the same as well as continuous bending moment through attaching arms being fixed to the back sides of the chains. That is why the chains tend to bend by the joints of the same during use. This naturally causes problems, when the scraper bars are aimed to be kept in a perpendicular position, for example against the bottom during use of the same. Additionally because of the reasons described above all service and maintenance measures, for example because of breakage of the scraper bars often cause long terminations for use. One crucial disadvantage of the type of scraper bars represented above is furthermore that, that they must be changed as a whole, that is very expensive when scraper bars, for example made of fiberglass are being used.
On the other hand from the following documents: U.S. Pat. No. 4,747,481, U.S. Pat. No. 4,722,434, CH 554 791 ja GB 2 133 763, it is previously known to exploit a bar entirety that is formed of bar parts to be connected to each other. All of the solutions being presented in the above documents are, however, conveyors, that are ment particularly for transfering of material, that is so called pusher or scraper conveyors. Due to deviating purposes of use in each solution above there has been exploited a so called link chain. The operating reliability of the link chain is particularly in the purpose of the invention in question most probably unsatisfying. In addition to that, when this type of chain is being used the drive and turning wheels must be replaced with very short intervals particularly because of wearing, that is due to those unproportionately high surface loads.